A color wheel is a key component of a projection display device that generates light required for imaging. In laser display technology, the color wheel carries a wavelength conversion material that converts a light beam from a solid state light source into an excited light of a desired wavelength. A large amount of heat will be generated during the process of converting the light beam from the solid state light source into the excited light by the color wheel, and the light conversion efficiency of the wavelength conversion material will be influenced if the heat cannot diffuse timely. In addition, the dust also has a great influence on heat-diffusion and conversion efficiency of the color wheel, and if the dust accumulates on the color wheel, the portion carrying dust will easily cause the rapid accumulation of heat, and moreover, in severe cases, the color wheel will be burnt.